Ampelographic evaluation of clone candidates of the 'Graševina bijela' (Vitis vinifera L.) in the vineyards of Zagreb

Graševina bijela najzastupljenija je i gospodarski najvažnija sorta u Republici Hrvatskoj. Njezina prilagodljivost na klimatske uvjete jedna je od brojnih karakteristika koje ovu sortu čine popularnom među vinogradarima. Uočena je unutarsortna varijabilnost među populacijom Graševine bijele zbog čega je 2004. godine pokrenut projekt klonske selekcije na području Kutjeva. U tom periodu, pa do 2015. godine odabrano je 12 klonskih kandidata koji su se istaknuli od ostatka populacije po pozitivnim osobinama. Ovih 12 klonskih kandidata posađeno na Vinogradarsko i vinarsko pokušalište u Jazbini s ciljem daljnjeg proučavanja njihovih karakteristika te nastavka postupka individualne klonske selekcije. Nakon ulaska nasada u puni rod, u 2017. godini provedeno je proučavanje najbitnijih gospodarskih karakteristika. Utvrđene su signifikantne razlike između klonova za svojstva: prirod, broj grozdova po trsu i osnovni pokazatelje kakvoće mošta. Kod četiri klona koja su se istaknula od ostatka populacije proveden je postupak mikrovinifikacije. Zatim je obavljena osnovna fizikalno-kemijska analiza vina te organoleptičko ocjenjivanje. Priznavanjem ova četiri klona omogućena je proizvodnja certificiranog sadnog materijala-klonova sorte Graševina u Republici Hrvatskoj.Graševina bijela is the most represented and economically most important variety in the Republic of Croatia. It’s adaptability to climatic conditions is one of many characteristics which makes this variety popular among wine growers. Internal variability was detected among population of Graševina bijela which is the reason why is the project of clonal selection in Kutjevo initiated in 2004. From that period up to 2015, 12 clone candidates were selected, which were distinguished with positive characteristic from the rest of the population. Then, these 12 clone candidates were planted in the vineyard at the Experimental Station Jazbina for the purpose of the future study of their characteristics and for continuing process of the individual clonal selection. The study of the important economic characteristics was carried out in 2017 when the vineyard came into full growth. There were significant differences between clones properties such as yield, number of clusters per vine and the basic quality indicators of the must. Four clones were distinguished from the rest of the population and with them, the microvinification process was done. Then, the basic physicochemical analysis and organoleptic evaluation of the wine was done. Recognition of these four clones enabled the production of certified plant material-clones of variety Graševina bijela in the Republic of Croatia